Early treatment of avascular necrosis in systemic lupus erythematosus.

Avascular necrosis (AVN) of the hips is associated with significant disability, and the majority of established cases require major surgery. In a retrospective analysis of 185 patients with systemic lupus erythematosus (SLE) 13 (7%) were found to have AVN. Of these, six had Raynaud's phenomenon, all had been on corticosteroids, and one had digital vasculitis. The mean duration of corticosteroid therapy was two years (range four months to five years). Five patients developed AVN two to 10 years after discontinuing steroids. The mean duration of disease at the onset of AVN was 6.85 years (range 1-19 years), and the mean age at onset of AVN was 31 years. Ten patients had severe multisystem involvement. None of the patients abused alcohol. Surgery was performed on 11 hips. Three had total hip replacement for stages 3 and 4 and seven had core decompression for stages 1 and 2. AVN progressed in two (28%) of these patients. In another patient core decompression failed for technical reasons. She subsequently required total hip replacement. The early detection of AVN to avoid the need for major surgery is stressed.     

Efficacy of alendronate, a bisphosphonate, in the treatment of AVN of the hip. A prospective open-label study

OBJECTIVE: To study the efficacy of alendronate, in the treatment of avascular necrosis (AVN) of the hip. METHODS: Sixty patients with AVN of the hip (100 hips with AVN) were studied. The follow-up period ranged from 3 months to 5 yr. The most common cause of AVN was steroids. Parameters studied were walking time, standing time, pain and disability on a visual analogue scale (VAS), range of motion of the hip, X-ray and MRI of the hip. All patients were treated with alendronate 10 mg/day (or 70 mg/week) along with 500-1000 mg of daily calcium and vitamin D supplements, and were advised to avoid weight-bearing. NSAIDs and analgesics were permitted as needed and were recorded. RESULTS: Forty-one patients (71 AVN hips) with AVN have been followed up for a minimum of 1 yr, 24 patients (42 AVN hips) for 2 yr and 21 patients (37 AVN hips) for more than 2 yr (average 37 month). Fourteen patients have been followed up for less than 1 yr (3-9 months). Significant reduction in pain and disability scores (P < 0.001) and significant increase in standing and walking time (P < 0.001) were observed. All hip movements improved at 1 yr (P value 0.000-0.009) with an insignificant decline after that (P > 0.001). Radiologically, the hips either stabilized in the same grade or progressed by one grade. MRI showed a decrease in marrow oedema in most cases at the 1-yr follow-up. Six patients (10 hips) required surgery and there were two (three hips) dropouts. The drug was well tolerated and there was a reduction in NSAID requirement. CONCLUSION: Alendronate reduces pain, improves function and retards AVN progression. Early surgical intervention can be avoided in most patients.     

Avascular necrosis of bone after adult acute lymphocytic leukemia treatment with methotrexate,vincristine, L-asparaginase,and dexamethasone (MOAD)

Four of 55 (7%) adult acute lymphocytic leukemia patients, age 27–58 years, who were treated with methotrexate, vincristine, L-asparaginase, and dexamethasone (MOAD) developed avascular necrosis (AVN) of one or both femoral heads 16–39 months after beginning treatment. All patients were treated with total joint replacement without compromise of quality of life during more than 3–9 years of follow-up, and they have remained in complete remission for a total of 6.5+ to 10.5+ years. A review of the literature revealed 11 previously reported cases of AVN of bone in patients with acute lymphocytic leukemia, 10 of whom received dexamethasone. The patients in the present report received a total dexamethasone dose equivalent to that of prednisone, 3.4–5.0 g/M². Although AVN of bone has been reported in patients receiving chemotherapy without corticosteroids, corticosteroids appear to be the most common class of agents associated with its development, and dexamethasone treatment may be more likely to result in AVN of bone than other corticosteroids, for unknown reasons. © 1996 Wiley-Liss, Inc.     

Risk of contralateral avascular necrosis (AVN) after total hip arthroplasty (THA) for non-traumatic AVN

The risk of developing bilateral disease progressing to total hip arthroplasty (THA) among patients who undergo unilateral THA for non-traumatic avascular necrosis (AVN) remains poorly understood. An analysis of the time-course to contralateral THA, as well as the effects of underlying AVN risk factors, is presented. Forty-seven consecutive patients who underwent THA for AVN were evaluated. Peri-operative and annual post-operative antero-posterior pelvis radiographs were examined for evidence of contralateral involvement. Patient age, weight, height, underlying AVN risk factor(s), date of onset of contralateral hip pain if occurred, and date of contralateral THA if performed, were recorded. Bone scan, computerized tomography and magnetic resonance imaging data were utilized when available. Twenty-one patients (46.6%) underwent contralateral THA for AVN within a median of 9 months after the initial THA (range 0–93, interquartile range 28.5 months). The median follow-up for patients without contralateral THA was 75 months (range 3–109, interquartile range 69 months). Thirty-four patients had radiographic findings of contralateral AVN at study entry; 25 were symptomatic bilaterally at entry and 7 developed contralateral symptoms within a mean time of 12 months (median 10 months, interquartile range 12 months). None of the 13 patients who were free of radiographic evidence of contralateral AVN at study entry developed evidence of AVN during the follow-up. AVN associated with glucocorticoid use was more likely to manifest as bilateral disease than either idiopathic AVN or ethanol-associated AVN (P=0.02 and P=0.03 respectively). Radiographically-evident AVN in the contralateral hip at THA is unlikely to remain asymptomatic for a prolonged period of time. Conversely, asymptomatic contralateral hips without radiographic evidence of AVN are unlikely to develop clinically significant AVN.     

Outcome of total hip replacement for avascular necrosis in systemic lupus erythematosus

OBJECTIVE: To describe the short and medium term results of total hip arthroplasty (THA) for avascular necrosis in patients with systemic lupus erythematosus (SLE). METHODS: Nineteen patients with SLE and avascular necrosis of the femoral head (AVNFH), who underwent 26 THA were retrospectively reviewed with a minimum followup of 2 years. To determine whether these patients had results similar to those of patients with other conditions, we formed a control group of 19 patients who had 29 THA. They were matched for age, sex, and followup to the patients with SLE. Controls had THA for juvenile rheumatoid arthritis (n = 7), osteoarthritis (5), adult onset rheumatoid arthritis (8), developmental dysplasia of the hip (4), and other diagnoses (5). Outcome measures included a 10 point visual analog scale (VAS) for pain, the Harris hip score, and the SF-36 self-administered health outcome questionnaire. We used the methods of Delee, Harris, and Engh for radiological assessment. RESULTS: Mean age at surgery was 46 years (range 21-71 years) and average followup was 4 years, 7 months (range 1 yr 9 mo to 9 yrs 6 mo), similar in both groups. Technical problems, mostly consisting of small, nonpropagating cracks of the calcar in uncemented stems, were encountered in 4 SLE hips and 1 control hip. Six complications were noted in the SLE group, including 2 early, nonrecurrent dislocations, 1 patient with thigh pain for 1 year, 1 pericarditis, 1 sick-sinus syndrome, and 1 urinary tract infection. There was one case of urinary tract infection in the control group. One SLE patient developed a low grade prosthetic infection and underwent successful revision 2 years after primary surgery. Clinical outcome measures had similar scores in the 2 groups: average VAS pain score = 2.00 in SLE hips (maximum 10) and 1.97 in control hips; mean Harris hip score = 86.7 in SLE patients (maximum 100) and 81.9 in controls; average SF-36 score = 63.4 in SLE patients (maximum 100) and 60.5 in controls. There was no radiological evidence of implant loosening in controls; there was 1 asymptomatic cup migration in the SLE group. CONCLUSION: In the short and medium term, patients with SLE and AVN had good results after THA. Results were similar in patients who had hip replacement for other diagnoses. Less favorable clinical outcomes of hip replacement have been reported in young patients who have AVN of other etiology (e.g., alcoholic, post-traumatic), but this was not the case in our young patients who had AVN and SLE. Thus, AVNFH and SLE should not constitute a contraindication to hip replacement.     

AVASCULAR NECROSIS OF THE HIP IN SYSTEMIC LUPUS ERYTHEMATOSUS: THE ROLE OF MAGNETIC RESONANCE IMAGING

The value of magnetic resonance imaging (MRI) in the early diagnosisof avascular necrosis (AVN) of the hip in SLE was investigated. Twenty females with severe SLE were studied prospectively. Eachunderwent 6-monthly X-rays, technetium -99m (Tc-99m) pyrophosphatebone scans and MRI of the hips over a 3-yr period. AVN was diagnosed in five hips of three patients (15%) duringthe study period. It was confirmed histologically in three hipsof two patients who underwent core decompression. Radiologicalevidence of AVN was present in two patients at diagnosis. Onepatient developed progressive radiological changes despite coredecompression. Bone scintigraphy was abnormal at some stagein all three patients with AVN however failed to detect theearly ischaemic stage of AVN. MRI was the most reliable investigation and was able to detectasymptomatic AVN prior to the appearance of radiological orscintigraphic abnormalities. KEY WORDS: Osteonecrosis, Core decompression, Femur     

Multifocal avascular necrosis after liver transplantation: an unusual presentation of the antiphospholipid syndrome

We describe the case of a 31-year-old man who presented with an antiphospholipid syndrome (APS), which manifested as multifocal avascular necrosis (AVN) one year after orthotopic liver transplantation. The patient developed multiple AVN affecting hips, left knee, humerus and tarsal bones just after withdrawal of corticosteroid therapy. Three years later when lupus anticoagulant was detected, he began anticoagulant treatment and no further AVN episodes were observed. It is important to be aware of this clinical manifestation of APS, especially in these cases where it can be easily overlooked because of corticosteroid therapy.     

Core decompression in avascular necrosis of the hip in sickle-cell disease

Sickle-cell disease (SCD) is the most common cause of avascular necrosis (AVN) of the hip in childhood. It results in significant physical impairment and chronic pain, and often progresses to require hip replacement. Conservative therapy is ineffective. We evaluated whether core decompression can arrest progression of AVN. We performed 13 coring procedures in 10 patients with SCD and AVN. Patients ranged from age 9–21 years at diagnosis (mean, median age, 15 years); five hips were stage I, six hips were stage II, and two hips were stage III. Mean follow-up on these patients was 3.7 years. Efficacy of the procedure was evaluated by clinical improvement in pain, radiographic progression, and need for further surgery. All 5 stage I patients had substantial improvement in pain, and only one showed X-ray progression. Five of the 6 (83%) stage II patients had improvement in pain, and 2 patients progressed on X-ray. Both stage III patients progressed on X-ray, but one was clinically improved. None of the 10 patients has required further surgery. Our results demonstrate that in early AVN, core decompression was beneficial for almost all patients, even with progression on X-ray. Core decompression should be considered in the management of SCD patients with early AVN. © 1996 Wiley-Liss, Inc.     

Avascular necrosis after treatment of aplastic anaemia with antilymphocyte globulin and high-dose methylprednisolone

Summary. Avascular necrosis of bone (AVN) occurring in patients with aplastic anaemia (AA) treated with antilymphocyte globulin (ALG) followed by high-dose methylprednisolone (HDMP) has been studied retrospectively. Out of 49 patients treated at two centres, seven have developed AVN at a median of 14 months (range 6–30) following treatment. The cumulative incidence of AVN is 21% (95% confidence intervals 7–35%). The hip was involved in six patients, bilaterally in five. Two patients had more than two joints affected. Surgical intervention was necessary in five patients, three of whom required total hip replacement. In contrast, there were no cases of AVN in a historical group of 61 patients with aplastic anaemia treated with an indentical regimen of ALG but using a short course of low-dose prednisolone. Lack of convincing evidence for benefit, the considerable morbidity from AVN, and increased risk of early life-threatening infection, suggest that high-dose methyl prednisolone should be omitted from ALG treatment protocols for aplastic anaemia.     

Outcome of total hip arthroplasty for avascular necrosis of femoral head in systemic lupus erythematosus patients: A comparative study

BackgroundAvascular necrosis (AVN) is a major cause of disability in systemic lupus erythematosus (SLE) patients which directly affects the functionality and quality of life. Total hip arthroplasty (THA) is indicated for severe cases with major disability and severe pain. It is still debatable if SLE is an independent risk factor for poor outcome in THA or not.Aim of the workTo evaluate the result of THA for AVN of the femur head in SLE patients.Patients and methods22 THAs were performed in 20 SLE patients and were compared with the results of 25 hips of 22 patients who had THA due to AVN with non-SLE conditions. All patients were followed up after the surgery at 6 weeks, 3, 6 and 12 months post-operatively, and then yearly for functional and radiological outcomes.ResultsThe Harris hip score (HHS) increased from a preoperative average of 26 points to 93.52 at the most recent follow-up. In the control group, the mean HHS was 26 preoperatively and 95.52 postoperatively at the last follow-up. Visual analog scale for pain (VAS pain) decreased from 8 in SLE and 6 in the non-SLE group to 2 and 1 respectively. No significant difference was found between SLE patients and non-SLE patients regarding complications except for more chest infections in the SLE group. No mortality was recorded in both groups in the postoperative follow-up period of a mean of thirty months.ConclusionTHA outcome is as favorable in AVN patients with SLE as in non-SLE.     

Asymptomatic avascular necrosis in patients with primary antiphospholipid syndrome in the absence of corticosteroid use: a prospective study by magnetic resonance imaging

OBJECTIVE: To evaluate the prevalence of avascular necrosis (AVN), using magnetic resonance imaging (MRI), in patients with primary antiphospholipid syndrome (APS) and in patients with systemic lupus erythematosus (SLE), with or without anticardiolipin antibodies (aCL), who are asymptomatic for AVN and have not taken corticosteroids. METHODS: Seventy-nine subjects who were asymptomatic for AVN were evaluated by MRI of the femoral heads: 30 patients with primary APS who had never received corticosteroids, 19 SLE patients who had never received steroids (divided into 2 groups, aCL positive and aCL negative, in order to examine any association between AVN and aCL), and 30 healthy subjects who were age- and sex-matched with patients with primary APS. Established MRI criteria were used for a diagnosis of AVN. RESULTS: Asymptomatic AVN was evident in 6 (20%) of 30 patients with primary APS: 3 of them (1 man, 2 women) had intermediate bilateral AVN, and 3 (all women) had early AVN (bilateral in 1 patient). Results of hip and pelvis radiography and dynamic scintigraphy were negative. Followup MRI 6 months later revealed no changes. At the time of the initial MRI examination, the mean (+/-SD) age of patients in whom AVN was identified was 31.2 +/- 7.3 years, and that of patients without AVN was 42.4 +/- 11.9 years (P = 0.036). Livedo reticularis occurred significantly more commonly in the group with AVN (P = 0.041). None of the healthy subjects and none of the patients with SLE demonstrated AVN on MRI. CONCLUSION: AVN can be detected by MRI in 20% of patients with primary APS. Younger patients tend to develop AVN more frequently than do older patients, and the presence of livedo reticularis may identify individuals at risk for AVN. Clinicians should be aware of this possible clinical manifestation of primary APS, because early diagnosis can lead to early intervention.     

Timing of initiation of enzyme replacement therapy after diagnosis of type 1 Gaucher disease: effect on incidence of avascular necrosis

Data from the International Collaborative Gaucher Group Gaucher Registry were analysed to assess the relationship between enzyme replacement therapy with imiglucerase (ERT) and incidence of avascular necrosis (AVN) in type 1 Gaucher disease (GD1), and to determine whether the time interval between diagnosis and initiation of ERT influences the incidence rate of AVN. All patients with GD1 enrolled in the Gaucher Registry who received ERT and did not report AVN prior to starting therapy ( n  = 2700) were included. The incidence rate of AVN following initiation of ERT was determined. An incidence rate of AVN of 13·8 per 1000 person-years was observed in patients receiving ERT. Patients who initiated ERT within 2 years of diagnosis had an incidence rate of 8·1 per 1000 person-years; patients who started ERT ≥2 years after diagnosis had an incidence rate of 16·6 per 1000 person-years. The adjusted incidence rate ratio was 0·59 [95% confidence interval (CI) 0·36–0·96, P  = 0·0343]. Splenectomy was an independent risk factor for AVN (adjusted incidence rate ratio 2·23, 95% CI 1·61–3·08, P  < 0·0001). In conclusion, the risk of AVN was reduced among patients who initiated ERT within 2 years of diagnosis, compared to initiating treatment ≥2 years after diagnosis. A higher risk of AVN was observed among patients who had previously undergone splenectomy.     

Bilateral avascular necrosis of both hips and both shoulders in a case with systemic lupus erythematosus: What should we blame,steroid or secondary antiphospholipid syndrome?

A 38‐year‐old female patient was diagnosed as a case of systemic lupus erythematosus (SLE) in 1994. Her initial presentation was nephritis which remitted on combination of steroid, azathioprine and pulse cyclophosphamide therapy. One year later the patient developed bilateral avascular necrosis (AVN) both hips and underwent bilateral hip replacement. In 2003 the patient developed bilateral AVN of both shoulders. In view of this uncommon presentation the patient screened for hidden secondary antiphospholipid syndrome and surprisingly investigations revealed negative anticardiolipin antibodies, weakly positive lupus anticoagulant test and positive reactivity against β2 glycoprotein 1. Although steroid is well know for its major role in AVN in patients with SLE, the presence of hidden secondary antiphospholipid syndrome augments the deleterious effects of steroid on bone and leads to AVN in uncommon sites. It is suggested that in SLE patients with positive lupus anticoagulant and negative antiphospholipid antibodies, testing for reactivity against β2 glycoprotein 1 is mandatory.     

Avascular necrosis of bone following intensified steroid therapy for acute lymphoblastic leukaemia and high-grade malignant lymphoma

Five out of nine adults (55%) with lymphoblastic disease developed severe avascular necrosis of bone (AVN) when treated with a Berlin-Frankfurt-Munster (BFM) ALL protocol similar to the current joint MRC–ECOG ALL trial (UKALL XII). The principal purpose of these intensified regimens is to improve long-term disease-free survival without necessarily increasing toxicity and secondary morbidity. The presentation of all five was non-specific bone pain occurring after the re-intensification block of chemotherapy containing high doses of dexamethasone. Three types of diagnostic imaging were performed and magnetic resonance imaging (MRI) proved superior in demonstrating AVN and showed it at an earlier stage than plain radiographs or isotopic scans. We believe that the dose of corticosteroids was the major factor in the development of AVN. The five men in our series all remain in first remission with a median disease-free survival of 3·5 years (range 2–8 years) but with varying degrees of disability due to AVN. Clinicians involved in UKALL XII and similar trials should be aware of this debilitating and potentially crippling complication when using high-dose steroid-containing regimens, perform MRI scan early and modify treatment if necessary.     

Avascular necrosis of the femoral head in sickle cell syndrome: a report of 5 cases

The course and management of avascular necrosis of the femoral head (AVNFH) in six hips of 5 sickle cell syndrome patients (3 with Hb SS, 1 with Hb SC and 1 with Hb S/beta+-thalassaemia) are described. Two patients (aged 13 and 17 years) presented with Perthes- and osteochondritis dessicans-type lesions. These hips progressed to roller-bearing-type joints with good function and no pain following conservative management of weight restriction and rest. Three patients (aged 14, 22 and 30 years at original presentation) suffered whole-head necrosis. Initially, these 3 patients had four hip joints replaced, two cemented-stemmed types, one cemented double-cup and one uncemented hemi-arthroplasty. All four joints failed and were revised 21-61 months after the original operation. One of the revision hips has now failed and is awaiting further surgery. These results demonstrate that it is very difficult to achieve a successful hip arthroplasty in the sickle cell syndrome patient.     

Synovial fluid β-endorphin level in avascular necrosis,rheumatoid arthritis,and osteoarthritis of the femoral head and knee. A controlled pilot study

The goal of this study is to determine and compare the β-endorphin levels in the synovial fluid of patients with different joint disorders (avascular necrosis, AVN; osteoarthritis, OA; and rheumatoid arthritis, RA of the hip or knee). Eighty-seven patients were involved in our study with an average age of 62 years. Thirty-three patients had AVN (18 hips, 15 knees). Twenty-three patients were diagnosed with OA (14 hips, 9 knees), and 31 patients suffered from RA (12 hips, 19 knees). We measured the β-endorphin levels of the synovial fluids -harvested from surgery—with radioimmunoassay. No significant difference was found in the β-endorphin levels of the synovial fluid from AVN comparing to OA and RA, however β-endorphin level was significantly higher in RA group than among patients with OA (p = 0.01). Synovial β-endorphin level was slightly lower in knee comparing to hip joint p = (0.06). When examining the different joints separately in compliance with diagnoses, we concluded that the synovial β-endorphin level from AVN was between the values of OA and RA without significant difference, whereas it was significantly higher in the knee of RA, than of OA groups (p = 0.05 knee, p = 0.2 hip). Our results confirmed those experiments which stated that there is a significant increase in synovial β-endorphin level in patients with inflammatory autoimmune diseases (e.g., RA), comparing to the level measured in degenerative conditions (e.g., OA).     

The efficacy and safety of intraarticular corticosteroid therapy for coxitis in juvenile rheumatoid arthritis

OBJECTIVE: To study the efficacy and safety of intraarticular triamcinolone hexacetonide (IATH) for the treatment of coxitis in patients with juvenile rheumatoid arthritis (JRA). METHODS: Fifty consecutive patients with JRA and coxitis were studied prospectively. Forty-eight children received IATH in 67 arthritic hips. The remaining 2 children exhibited 3 cases of femoral head necrosis (FHN) at the initial assessment and were only followed up; both were receiving long-term systemic steroids. After a minimum of 2 years, the study was concluded with a final evaluation that included magnetic resonance imaging. RESULTS: In 39 of 67 hip joints (58%), remission of the coxitis for a period of 2 years was obtained through a single administration of IATH, while another 12 hip joints showed remission of coxitis after repeated TH injections (total remission rate 76%). We observed 2 patients with FHN following IATH. Both of these children were receiving long-term systemic steroids. During the period between onset of JRA and screening assessment for this study, the children exhibited 2.4 cases of FHN per 100 patient-years, while 1.5 cases of FHN per 100 patient-years were observed between IATH treatment and final followup. All 5 observed cases of FHN occurred among the 20 children who received long-term systemic steroids, while no necrosis occurred in the 30 children who did not receive systemic corticosteroids (P = 0.009 by Fisher's exact test). CONCLUSION: IATH for juvenile rheumatoid coxitis was an effective treatment that did not increase the rate of FHN. Systemic steroids, however (or their covariable, severity of JRA), may increase the risk of FHN in JRA.     

Multiple avascular necrosis of bone and polyarticular septic arthritis in patients with systemic lupus erythematosus

Objective Avascular necrosis of bone (AVN) and osteoarticular infection share similar risk factors in systemic lupus erythematosus (SLE) patients. However, their coincidental development in SLE has rarely been described. We describe four cases of AVN complicated by Staphylococcus aureus infection in SLE.Methods Patients were identified by retrospectively reviewing an SLE cohort followed between 1979 and 2003. A review of the literature from 1960 until 2003 was also done.Results Among 315 SLE patients, four developed joint infection by S. aureus following or coincidentally with AVN. All presented multifocal disease with severe or relapsing course, resulting in severe incapacity. The clinical course suggests that AVN developed first in active SLE patients with positive antiphospholipid (aPL) antibodies treated with high-dose corticosteroids (CS), and subsequent bone infarcts favor infection. Our patients often required prolonged antibiotic therapy and surgical treatment.Conclusions Active SLE patients with aPL antibodies on high-dose CS seem at high risk of developing multiple AVN complicated by infection. Avascular necrosis and bone or joint infection by S. aureus in these patients is a major complication that leads to severe joint destruction and disability.     

Distribution of hip pain in osteoarthritis patients secondary to developmental dysplasia of the hip

Objectives

Our aim was to clarify the distribution of hip pain in patients with osteoarthritis of the hip secondary to developmental dysplasia of the hip (DDH).

Methods

We retrospectively studied 443 hips in 369 patients with osteoarthritis secondary to DDH; mean age was 61 years, and follow-up rate was 84 %. Hip pain was defined as preoperative pain that was relieved 3 months after total hip arthroplasty.

Results

Distribution of pain originating in the hip was 89 % (393 hips) to the groin, 38 % (170 hips) to the buttock, 33 % (144 hips) to the anterior thigh, 29 % (130 hips) to the knee, 27 % (118 hips) to the greater trochanter, 17 % (76 hips) to the low back, and 8 % (34 hips) to the lower leg. When the groin, buttock, and greater trochanter were combined as the hip region, 95 % (421 hips) of pain was located in the hip region. On the other hand, when the anterior thigh, knee, lower leg, and low back were combined as the referral region, 55 % (242 hips) showed referred pain.

Conclusions

We suggest that rheumatologists be aware of hip disease masquerading as knee pain or low back pain.     

The economic impact of SARS in Beijing, China

Objective  To document the impact of the severe acute respiratory syndrome (SARS) outbreak in Beijing on indicators of social and economic activity.
Methods  Associations between time series of daily and monthly SARS cases and deaths and volume of public train, airplane and cargo transport, tourism, household consumption patterns and gross domestic product growth in Beijing were investigated using the cross-correlation function.
Results  Significant correlation coefficients were found for all indicators except wholesale accounts and expenditures on necessities, with the most significant correlations occurring with a delay of 1 day to 1 month.
Conclusions  Especially leisure activities, local and international transport and tourism were affected by SARS particularly in May 2003. Much of this consumption was merely postponed; but irrecoverable losses to the tourist sector alone were estimated at about US$ 1.4 bn, or 300 times the cost of treatment for SARS cases in Beijing.